arXiv subjects

R. Mittleman

Publications and source records attributed to R. Mittleman.

6 recordsLinked to original sources

arXiv2020

Frequency-Dependent Squeezing for Advanced LIGO

The first detection of gravitational waves by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 launched the era of gravitational wave astronomy. The quest for gravitational wave signals from objects that are fainter or farther away impels technological advances to realize ever more sensitive detectors. Since 2019, one advanced technique, the injection of squeezed states of light is being used to improve the shot noise limit to the sensitivity of the Advanced LIGO detectors, at frequencies above $\sim 50$ Hz. Below this frequency, quantum back action, in the form of radiation pressure induced motion of the mirrors, degrades the sensitivity. To simultaneously reduce shot noise at high frequencies and quantum radiation pressure noise at low frequencies requires a quantum noise filter cavity with low optical losses to rotate the squeezed quadrature as a function of frequency. We report on the observation of frequency-dependent squeezed quadrature rotation with rotation frequency of 30Hz, using a 16m long filter cavity. A novel control scheme is developed for this frequency-dependent squeezed vacuum source, and the results presented here demonstrate that a low-loss filter cavity can achieve the squeezed quadrature rotation necessary for the next planned upgrade to Advanced LIGO, known as "A+."

astro-ph.IM↗

arXiv2017

Control strategy to limit duty cycle impact of earthquakes on the LIGO gravitational-wave detectors

Advanced gravitational-wave detectors such as the Laser Interferometer Gravitational-Wave Observatories (LIGO) require an unprecedented level of isolation from the ground. When in operation, they are expected to observe changes in the space-time continuum of less than one thousandth of the diameter of a proton. Strong teleseismic events like earthquakes disrupt the proper functioning of the detectors, and result in a loss of data until the detectors can be returned to their operating states. An earthquake early-warning system, as well as a prediction model have been developed to help understand the impact of earthquakes on LIGO. This paper describes a control strategy to use this early-warning system to reduce the LIGO downtime by 30%. It also presents a plan to implement this new earthquake configuration in the LIGO automation system.

physics.ins-det↗

arXiv2016

Modeling and Experiment of the Suspended Seismometer Concept for Attenuating the Contribution of Tilt Motion in Horizontal Measurements

Tilt-horizontal coupling in inertial sensors limits the performance of active isolation systems such as those used in gravitational wave detectors. Inertial rotation sensors can be used to subtract the tilt component from the signal produced by horizontal inertial sensors, but such techniques are often limited by the sensor noise of the tilt measurement. A different approach is to mechanically filter the tilt transmitted to the horizontal inertial sensor, as discussed in this article. This technique does not require an auxiliary rotation sensor, and can produce a lower noise measurement. The concept investigated uses a mechanical suspension to isolate the inertial sensor from input tilt. Modeling and simulations show that such a configuration can be used to adequately attenuate the tilt transmitted to the instrument, while maintaining translation sensitivity in the frequency band of interest. The analysis is supported by experimental results showing that this approach is a viable solution to overcome the tilt problem in the field of active inertial isolation.

physics.ins-det↗

arXiv2016

Seismic isolation of Advanced LIGO: Review of strategy, instrumentation and performance

Isolating ground-based interferometric gravitational wave observatories from environmental disturbances is one of the great challenges of the advanced detector era. In order to directly observe gravitational waves, the detector components and test masses must be highly inertially decoupled from the ground motion not only to sense the faint strain of space-time induced by gravitational waves, but also to maintain the resonance of the very sensitive 4 km interferometers. This article presents the seismic isolation instrumentation and strategy developed for Advanced LIGO interferometers. It reviews over a decade of research on active isolation in the context of gravitational wave detection, and presents the performance recently achieved with the Advanced LIGO observatory. Lastly, it discusses prospects for future developments in active seismic isolation and the anticipated benefits to astrophysical gravitational wave searches. Beyond gravitational wave research, the goal of this article is to provide detailed isolation strategy guidelines for sensitive ground-based physics experiments that may benefit from similar levels of inertial isolation.

physics.ins-det↗

arXiv2013

Hydraulic External Pre-Isolator System for LIGO

The Hydraulic External Pre-Isolator (HEPI) is the first 6 degrees of freedom active seismic isolation system implemented at the Laser Interferometer Gravitational Wave Observatory (LIGO). Implementation was first completed at the LIGO Livingston Observatory (LLO) prior to LIGO's 5th science run, successfully cutting down the disturbance seen by LLO's suspended optics in the two most prominent seismic disturbance bands, the microseism (0.1-0.3Hz) and the anthropogenic (1-3Hz) bands, by a factor of a few to tens. The improvement in seismic isolation contributed directly to LLO's much improved duty cycle of 66.7% and LIGO's triple coincident duty cycle of 53%. We report the design, control scheme, and isolation performance of HEPI at LLO in this paper. Aided with this success, funding for incorporating HEPI into the LIGO Hanford Observatory was approved and installation is currently underway.

gr-qc↗

arXiv1999

Past electron-positron g-2 experiments yielded sharpest bound on CPT violation for point particles

In our past experiments on a single electron and positron we measured the cyclotron and spin-cyclotron difference frequencies omega_c and omega_a and the ratios a = omega_a/ omega_c at omega_c = 141 Ghz for e^- and e^+ and later, only for e^-, also at 164 Ghz. Here, we do extract from these data, as had not done before, a new and very different figure of merit for violation of CPT symmetry, one similar to the widely recognized impressive limit |m_Kaon - m_Antikaon|/m_Kaon < 10^-18 for the K-mesons composed of two quarks. That expression may be seen as comparing experimental relativistic masses of particle states before and after the C, P, T operations had transformed particle into antiparticle. Such a similar figure of merit for a non-composite and quite different lepton, found by us from our Delta a = a^- - a^+ data, was even smaller, h_bar |omega_a^- - omega_a^+|/2m_0 c^2 = |Delta a| h_bar omega_c/2m_0 c^2) < 3(12) 10^-22.

hep-ph↗